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FROM CHURCH BELLS TO ELECTRIC SIGNALS 


A story of the 
Chicago Fire Alarm System 
1940 


Sponsored by the 
BOARD OF EDUCATION OF CHICAGO 
William H. Johnson, Superintendent 

Compiled by the 

WORKERS OF THE WRITERS’ PROGRAM 
of the 

WORK PROJECTS ADMINISTRATION 
in the State of Illinois 

Assisted by the Faculties 
and 

Pupils of the Social Studies 
Workshop Schools 

Minnie E. Fallon, Assistant 
Superintendent, Chairman 
Ella M. Flynn, Executive 
Secretary 

Bertha F. Royals, Teacher 
Consultant 


Illustrated by the Illinois Art Project 


FEDERAL WORKS AGENCY 
John M. Carmody, Administrator 
WORK PROJECTS ADMINISTRATION 
Howard 0. Hunter, Acting Commissioner 
Florence Kerr, Assistant Commissioner 
Charles E. Miner, Administrator for Illinois 
Evelyn S, Byron, Director Professional and Service Section 


















"T l^“7 2.71 

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AUTHOR 1 B P a A F A C £ 


This pamphlet is one of the "Know Chicago" series of book¬ 
lets, designed and especially written for 8A Social Studies 
in the Chicago Public Schools. The writer of each booklet 
in the series read at least one chapter of his manuscript to 
an 8A class in a social studies workshop school and made 
changes based on the reactions of the boys and girls in his 
audience. 

The social studies worksho-ps are schools where teachers and 
pupils are laboring to gain a deeper understanding of their 
country and its 'problems and of those of the rest of the 
world the while they live and work together according to the 
American Way of Life. 

The booklet has been made possible in large cart through the 
courtesy and co-operation of Michael J. Corrigan, fire com- 
missioner, City of Chicagoj John T. Gegan, chief fire alarm 
operator; Michael J. Hanley, chief of fire alarm wires; the 
National Board of Fire Underwriters,Chicago; and the Game- 
well Company of Chicago. 

For the history of the alarm system up to the opening of the 
present century, the author is indebted chiefly to A Synou- 
tpc history of the Chicago Fire Department, compiled and 
edited by James S. McQuade, and the Andreas' History of 
Chicago . - 


Herman A. Dick, 
the author. 











FROM CHURCH BELLS TO ELECTRIC SIGNALS 


The Story of the Chicago Fire Alarm System 

When Chicago firemen refer to their alarm system as the 
finest or the fastest in the world, they are thinking not so 
much of the alarm equipment itself, good as it is, but of 
the speed with which the system operates. In Chicago an 
alarm of fire is frequently transmitted from the central of¬ 
fice to the company or companies which are to respond to it 
in a little less time than i t takes in other large cities 
under similar conditions. 

To us a few seconds may not seem important, but firemen know 
that seconds gained may mean the saving of lives and property 
which would otherwise be lost or destroyed, In the early 
stages of a fire, particularly are those seconds important, 
for the amount of destruction per second increases as long 
as the fuel upon which the fire feeds is present. A fire is 
small when it starts and adding too much fuel in its early 
stages may put it out. But, the bigger the fire gets, the 
more the fuel it will consume in each second. That is why 
even seconds are important in the time necessary for firemen 
to got to a fire and to begin the work of putting it out. In 
large fires, destruction of property at the rate of $1,000 a 
minute is not unusual. The value of the property destroyed 
in the South Chicago grain elevator blaze of May 11, 1939, 
has been estimated at $2,500,000. Most of the destruction 
occured within a period of about two hours. 

The first alarm was sounded at 8:53 in the morning. More 
apparatus and men were summoned at short intervals until the 
last call at 10:43 a.m. Thus, within about two hours' time 
the fire was under control and from then on began to taper 
off in intensity, even though piles of grain continued to 
smolder for days and even weeks afterward. During the first 
two hours of that fire $1,500,000 worth of property was de¬ 
stroyed. That was at the rate of $12,500 per minute. 

The money value of property destroyed may not mean much to 
some of us, but when we learn that 10,000 lives are lost 






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every year in the United States by fire,, we can appreciate 
why Chicago’s fire fighters are proud of their alarm system 
and the advantage a few extra seconds gives them. 

This alarm system is the result of many experiments and im¬ 
provements during the period of one hundred years or more in 
which Chicago has had a fire department. 

Fire Alarms in Former Days 

Before the telegraph alarm was introduced, alarms of fire 
were sounded by the simple methods still used in many small 
toms—ringing a bell or striking a metal wagon wheel tire. 
Today we find it hard to believe that Chicago was once a 
small town; yet in 1833, when the ’’town” of Chicago was in¬ 
corporated, its population was less than 200 persons living 
and working in forty-three houses. A year before that 
Chicago had been a ’’frontier village of not more than half a 
dozen” wooden buildings. We do not know what means of 
sounding an alarm of fire was used during the first ten 
years of Chicago’s existence. The first recorded meanswas 
the ringing of a church bell. 

That was in 1844 and the bell hung in the tower of the Uni¬ 
tarian Church, then located at the northeast corner of Wash¬ 
ington and Dearborn Streets. Probably, before that time, an 
alarm was raised by shouting ’’Fire’.” By this means, not 
only the members o f the volunteer fire department but the 
entire population of the tom as well would be aroused. That 
■would not have been a difficult matter, for in the early 
town and city of Chicago the houses were grouped together in 
a narrow strip along the Chicago River. 

By 1844 Chicago had become a city of between 8,000 and 10,000 
inhabitants and had an area of nine square miles; yet the 
only official fire alarm ’’system” of the time seems to have 
been that bell in the Unitarian Church. The person who 
first saw a fire ran to the church and pulled the bell rope; 
the volunteer firemen came running to the church, if they 
had not, in the meantime, been informed as to the location 
of the fire. 


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In the following ten years the city grew rapidly. By 1855 
its area had increased to 17^ square miles, and its popula¬ 
tion to about 80,000 persons. The sound of the bell in the 
Unitarian Church could no longer reach all parts of the city. 
So the members of the First Baptist Church, then located at 
the southeast corner of La Salle and Washington Streets, of¬ 
fered the use of their bell for sounding alarms of fire in 
addition to calling the congregation to services. This was 
a larger bell than that of the Unitarian Church, and its 
ringing quality carried its tones much greater distances. 

So effective was the Baptist Church bell that the city fa¬ 
thers undertook to secure its use exclusively for fire 
alarms purposes. When, in 1855, the second courthouse was 
built where the City Hall and County Building now stand, the 
First Baptist Church bell was tiip4^Terred to the courthouse 
tower. Also at this time, a set of signals was introduced 
to indicate the general location of a fire. 

The tower of the courthouse was made the city’s official 
fire alarm station,and at all times, day and night, a watch¬ 
man was on duty in the tower to look out for fires and to 
report their location by signals. The code adopted in 1855 
was simple: first, eight strokes of the bell to attract at¬ 
tention, followed by a short pause; then, from one to six 
strokes to indicate in which of the city’s six districts the 
fire had broken out. 

A different code used before the Civil War was to hang out 
of the courthouse tower a certain number of flags or lan¬ 
terns, to tell the place of a fire—flags during the day and 
lantei^ft at night. The ringing of bells seems, however, to 
have been more satisfactory, for a bell can be heard as well 
by night as by day and at greater distances than flags o r 
lanterns can be seen. 

In addition to the bell i n the courthouse tower, smaller 
bells were, from time to time, placed in watch towers near 
fire stations in various parts of the city. When the man on 
duty in one of these towers saw a fire he sounded an alarm 
by means of his bell. Later, speaking tubes were installed 


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ill the towers so that the man on watch could talk to the men 
in the firehouse below and describe the location of the fire. 
Still later, toward the close of the nineteenth century, the 
watchtowers were equipped with telegraph instruments fdr 
sending this information. Even after the telegraphic alarm 
equipment had been installed, however, some of the smaller 
alarm bells continued to serve, though they had to play 
second fiddle to the alarm telegraph. Several of the small¬ 
er bells remained in use until 1900. 

Although in 1844 Samuel F. B. Morse demonstrated that the 
magnetic telegraph was practical.the principle was not ap¬ 
plied immediately to the design and construction o f tele¬ 
graph fire alarm systems. It wqs not until 1856 that public 
demonstration of a successful telegraphic fire alarm system, 
developed from Morse’s crude instruments and simple electric 
circuits, was held in the chamber of the Chicago city Coun - 
oil. But, the members of the council were not even then 
convinced of the need for the new system. 

The Telegraphic Alarm 

In May, 1863, .a city council committee was authorized to 
make a study of the telegraphic fire alarm. As a result of 
this committee’s recommendations, a contract for the instal¬ 
lation of such a system was let the following spring, A 
little more than a year later, in June, 1865, Chicago’s 
first fire alarm telegraph was turned over to the city 
authorities and placed in operation. -More than a year was 
needed to install this first telegraphic alarm system and 
place it in operation. It cost $70,000, 

The expenditure covered the cost of the central alarm office 
and equipment located in the dome of the courthouse; 106 
alarm and call boxes; 125 miles of electric wire, much of it 
running along the roofs of houses; 14 electric gongs in en - 
gine houses; 6 bell-striking devises; and 6 dial instruments 
which enabled members of the police department to set up 
fire alarm code numbers to be automatically transmitted to 
the alarm office. 


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During the next few years the system was extended. But in 
the fire of October, 1871, it received a serious blow. The 
great Chicago fire destroyed not only the central alarm of¬ 
fice but also forty-odd miles of wires, sixty fire alarm 
boxes, and other equipment.. 

The new system had become so important to the city that 
every effort was made to get it back into operation as soon 
as possible. In spite of confusion caused by the disaster, 
half the equipment - that on the near west side - was ready 
to use within two days. A week later, the south side was 
back to normal. Equipment and wire were purchased or borrow¬ 
ed from other cities and,'in some cases, make-shift electrio- 
al devices and apparatus were used, particularly on the near 
north side, where total destruction of the system occurred. 

One of the most difficult reconstruction problems was the 
placing of electric wire lines. The first telegraph alarm 
system, consisted of 125 miles of wires, and of these, 40 
miles were destroyed. One reason for so much destruction 
was that wires were usually strung over roofs, from building 
to building; hence, both wires and houses were burned, or 
the wires broke when their supports toppled. 

To get the alarm system back in operation,the city authori - 
ties had to replace those forty miles of wares. They could 
not, of course, be put back on houses which had been burned, 
and in addition so much building was going on in the down- 
tow;n district that, if -wires had been strung along roofs, 
they wrould have been broken. In fact, lines wrhich had not 
been destroyed in the fire, frequently met with such acci¬ 
dents. 

So the city began erecting its own poles for fire alarm 
lines and, in many cases, received permission to use the 
privately-owned poles of two telegraph companies—the Western 
Union Telegraph Company. In succeeding years, more and more 
poles -were added until, in 1876, . the last of the house-top 
wires had been removed from roofs. Also, about this time 
the alarm system 1 s first submarine or "under-water" cable 
was laid. That was across the north branch of the Chicago 
River at Chicago Avenue. 


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A few years after the Great Fire, John P. Barrett, who was 
then superintendent of the fire alarm system, urged that as 
many land wires as possible be placed in conduits under the 
ground, for protection against minor accidents and breakage. 
Expert electricians in other cities are said to have scoffed 
at the plan. Perhaps for this reason Barrett’s suggestion 
was not carried out at the time, and for many years all 
alarm wires—except those which ran under the Chicago River-- 
were placed on poles, a cheaper method than running wires in 
conduits underground, though not as safe. 

Still the men in charge of the alarm system continued to 
urge the placing of underground wires, and by the time of 
the first World's Fair in Chicago, 1893, none of the alarm 
lines in what is now the Loop district remained above ground. 
More and more miles of wire were placed underground every 
succeeding year until today, of Chicago’s 2,500 miles of 
alarm wires, about three-fourths are under-ground and only 
one-fourth on poles. 

The Joker and ’’Talking" Lines 


Four or five years after the fire of 1871 came the installa¬ 
tion of the joker^-an event which was to have a very great 
effect, not only on our own alarm system but on those of 
other cities. The "joker” is simply a telegraphic receiving 
set. It is a type of circuit which makes possible the send¬ 
ing of all alarms to all fire stations at once without add¬ 
ing any lines. We shall learn more about the joker late r 
on. 


During 1878 fourteen engine houses were connected with the 
central alarm office through what were named "talking" lines 
—to distinguish them from the telegraph lines. The name^ 
"talking line" has survived to this day to designate what 
are generally known simply as telephones. 

In the following years the installation of both "talking" 
and "joker" lines continued rapidly. In 1879, the practice 
of connecting the alarm office by telephone with police sta¬ 
tions, pumping stations, and other city administration 


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buildings was started. City employees, other than firemen, 
were thus enabled to send direct alarms to the fire depart¬ 
ment. By 1882, ’’joker” lines also were being installed in 
police stations. 

Toward the end of 1883,- every fire station had been connect¬ 
ed with the central alarm office by both telephone and tele¬ 
graph, and all police stations by telegraphic alarm lines. 
Today, however, only division headquarters of police are 
connected with the fire alarm office by telegraphic alarm 
lines. When fires require the services of policemen to han¬ 
dle traffic and keep over-curious citizens ’’out from under 
the feet” of firemen, divisional police headquarters now 
notify local district officers by telephone or radio. 

During the thirteen years between 1871 and 1884, not only 
the central alarm office but all city departments had been 
housed in the ’’old” Rookery, a two-story structure at the 
southeast corner of Adams and La Salle Streets, where now 
stands another building also called ’’The Rookery.” Chicago 
then boasted that it had the best-equipped fire alarm office 
in the world. That claim may have been the result of over¬ 
enthusiasm or it may have been a fact; which ever it was, it 
showed the spirit of a reborn Chicago. 

The city hall to which the fire alarm office was removed in 
1884 was the same structure in which the office is now 
housed, although the building stood on another site. The 
present city hall and fire alarm office were first occupied 
in 1911, 


Recent Progress 

The past fifty years have seen many changes and improvements 
in the alarm system. Most of these changes, however, have 
been of a highly-technical nature. 

In 1901 a ’’double joker” system replaced the ’’joker and 
transmitter” lines, which had been used previously. 

In 1911 a wall map was installed in the central alarm office 











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which showed by means of lights, all the fire stations in 
the city. This was of great value in relocating and dis¬ 
patching fire companies on second and other "extra" alarms. 
In 1940 a greatly superior wall map replaced the 1911 model. 

In 1927,after the fire department had been completely motor¬ 
ized and new companies and equipment had been added,the pre¬ 
sent "running card" schedule was first used. This tells 
which companies are to go out on each box alarm, and also 
provides for fourth and fifth alarms and for "automatic re¬ 
locations" - that is, moving companies to take care of dis¬ 
tricts of the city from which other companies have gone to 
fight a bad fire. 

In 1928 direct alarm lines were installed from a switchboard 
in the central alarm office to public utility companies 
whose services might be affected or interrupted by fires— 
utilities such as gas, electric, telephone, and transporta¬ 
tion lines. Such companies now r receive directly, by means 
of telegraphic alarm lines, all fire calls, both box and 
still. In the same year all fire stations were equipped with 
a second telephone line, known as the marshal’s line, which 
enabled fire marshals to hold direct conversations with com¬ 
pany officers and firemen. 

"Amplifiers" or loud speakers, which are now; used in all fire 
stations north of Pershing Hoad to report locations of still 
alarms, vrere first installed in 1938. In the district south 
of Pershing Road "still alarm" loud speakers are now being 
installed. 


Still and Box Alarms 


Just v;hen and how the expression "still alarm" originated we 
do not known Hov/ever, the term goes back to the days before 
telegraphic alarm systems and telephones had been invented, 
to the time vjhen the ringing of a bell or some similar means 
of sounding an alarm was used to call out volunteer firemen 
and other members of the community. If a blaze were not 
large or did not seem very dangerous, someone might summon a 
few firemen or neighbors without ringing the alarm bell and 
rousing the v;hole community. 


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In grandfather’s day a still alarm was one given at a fire¬ 
house by word of mouth,and the same term is used today. How¬ 
ever, its meaning has enlarged to include telegraphic and 
telephoned alarms, which compose 98 per cent of the total, 
less than 2 per cent being reported directly at fire houses^ 
Today almost 90 per cent of all fire alarms come in over 
telephones. 

Thus, the term "still alarm’* means any alarm which does not 
come into the central office from a box. 

While only about 8 per cent of all fire alarms come from 
boxes, they play an important part in the work of the fire 
department. Still and box alarms are not only received dif¬ 
ferently at the alarm office but are transmitted by somewhat 
different methods. Also fewer men and pieces of apparatus 
are sent out in response to a still alarm—unless the person 
reporting by telephone or in person indicates that the fire 
is serious or threatens to become serious. In that case, as 
many men and as much apparatus are sent as if the alarm had 
come from a box, but this averages only four out of every 
thousand fires reported by phone. 

Suppose a telephone message indicates that an automobile is 
on fire in the street-not in a garage. Probably only one 
engine will be sent to the scene, A small prairie blaze re- 
ported by telephone would be handled in the same way. 

If these same fires were reported by sending in an alarm 
from a nearby box, the fire department would send out all 
the equipment scheduled to answer an alarm from that parti¬ 
cular box. Perhaps two or three engines, one or two hook and 
ladder trucks, and possibly four or five other pieces of ap¬ 
paratus. Imagine,if you can^ what would happen to Chicago 
traffic if all that apparatus were sent out in answer to 
each of the twenty-odd thousand still alarms which come into 
the central office each year. 

Sending Still Alarms 

A telephoned alarm of fire is so easy to send in Chicago 
that even a small child can do it. All one needs to know is 


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his address and this number: Fire 1313 . That is the tele¬ 
phone number of the central fire alarm office. 

When a voice responds, ’’Fire Department,” give the street 
location of the fire. Speak distinctly; slowly, if neces¬ 
sary, but,, in any event, distinctly. 

Then, give the alarm office one more piece of information; 
that is, what is burning. That will help in determining the 
apparatus and equipment to send to the fire. 

Shortly after you have hung up the receiver,you will be able 
to hear the sound of a siren heralding the approach of an 
engine on its way to put out the fire you have reported. 

Should you make your call for the fire department over a 
dial telephone, you will dial F-I-B 1313 and, when the de¬ 
partment responds, give the necessary information. If you 
have any doubt of your ability to dial F-I-R 1313 correctly, 
you had best simply dial "Operator,” and, when the telephone 
girl answers, tell her you want Fire 1313. Then proceed just 
as previously outlined. 

For several reasons we have discussed telephoned alarms be¬ 
fore box alarms, for at least ten alarms are telephoned for 
every one sent through boxes. Also, there are about a mil¬ 
lion telephones,and only about 2,500 alarm boxes,in Chicago. 
Also a telephone is usually closer to the scene of a fire 
than the nearest alarm box. Often one can send an alarm by 
telephone without having to go outdoors or to dress fully. 
Finally, telephoned information about a fire makes it possi¬ 
ble for apparatus to proceed directly to the scene, instead 
of having first to go to the box from which an alarm has 
been sent and there learn the location of the fire. 

Sending Box Alarms 

Nevertheless, the box alarm, too, has advantages. Fires in 
schools, theaters, and other places where numbers of people 
gather should preferably be reported by the box alarm. Boxes 
are located at most mile and half-mile intersections and at 
some quarter-mile intersections, as well as in front ofscbodl^ 


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theaters, hospitals and other institutions and some large 
commercial and industrial plants. In the downtown district 
often several boxes have been placed on the same block. 

The mechanisms inside these boxes are all similar, though 
there are two distinct types of doors, called respectively, 
key and keyless doors. One should remember that with either 
type the alarm is sent only when the hook has been pulled 
down. One should also remember that after an alarm has been 
sent some one must remain at the box until the firemen come, 
in order to direct them to the exact location of the fire. 

The key-type door is opened by means of a key which may be 
obtained from a storekeeper nearby or,if there are no stores 
in the vicinity, from a householder, Twenty or more keys are 
generally available in the neighborhood of each box. A n 
alarm is sent from this type of box by opening the outer 
door with a key,and then pulling down a hook inside the box. 

The second type, called the ’’turn-handle” or keyless door, 
may be distinguished not only by the T-shaped handle on the 
outside but also by the fact that the front-door casing ex¬ 
tends several inches from the box proper. The key door, on 
the other hand, is flat and flush with the front edge of the 
box. 

The keyless-door is opened by turning the T-shaped handle to 
the right. Turning this handle rings a bell in the cover 
casing b ut does not send an alarm . The alarm is sent—as in 
the case of the key-door type of box—by pulling down a hook 
inside the box and then letting go. The purpose of the bell¬ 
ringing door handle is to give notice of the fact that some¬ 
one is sending an alarm, thus discouraging the sending of 
false alarms. Severe penalties are provided by law for mali¬ 
ciously or mischievously sending false alarms. 

In front of many schools there are alarm boxes with bell¬ 
ringing keyless doors.If a key-door box is used at a school, 
the office and the janitor or engineer keep the keys. 

The officer on the first piece of apparatus which arrives at 
the scene will, at a glance be able to tell whether a fire 


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is going to prove stubborn and will immediately summon more 
equipment if that seems necessary. 

Additional calls for apparatus and equipment are known in 
the department as "extra alarms" .and are designated by those 
somewhat mysterious symbols 2-11, 3-11, 4-11, and 5-11. They 
mean simply: second, third, fourth and fifth alarm, respect¬ 
ively. 

Previous to 1878 there was in the code a 6-11 or "general" 
signal. From 1878 to 1927 department practice provided for 
first, second, and third box alarms, followed by special 
calls for any additional apparatus needed. Under the present 
system, inaugurated in 1927, there are five regular box 
alarms which are followed by or include special calls. 

What apparatus moves in response to each box alarm is deter¬ 
mined by a schedule kept on "running cards," of which each 
station has a complete file. At an extra-alarm fire, the 
alarm box serves both as a means of communication with the 
fire department as a whole and as a center of operations. 
The officer in command uses it not only for sending regular 
extra alarms but also as a means of calling apparatus and 
equipment which is especially needed. In the back of each 
box is a telegraph key which is used for communication with 
the central alarm office. There is a telegraphic code sig¬ 
nal for every requirement which might arise at a fire. More 
engines than usual might be needed, or an ambulance, high- 
pressure apparatus, a gasoline supply truck; in fact, any 
apparatus not on the regular running schedule. If so, the 
officer need only send the appropriate signal. 

Suppose it is ambulances wtiich are needed. The officer tel¬ 
egraphs the signals 3-5, gives the number of ambulances de¬ 
sired, and finally the code number which is his own signature. 
In similar manner,special calls may be sent for a physician, 
a superior officer, or for additional apparatus. 

How? the Alarm System Works 


Let us at the outset fix in our minds two facts; first, that 
ail Chicago fire alarms pass through the central alarm of- 



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fice and., second, that all alarms, sooner or later, go to 
every fire house in the city. 

About 98 per cent of all alarms originate at places other 
than fire department buildings,go into the central alarm of¬ 
fice, and are relayed by that office not only to the company 
or companies which are to respond but also to all the other 
fire companies in the city. 

There is one exception to this general procedure. Some 500 
alarms a year are reported directly to fire houses. The com¬ 
pany receiving such a verbal alarm responds immediately, but 
not until the officer in charge has telegraphed the central 
office in code that his company is going out in response to 
a still alarm and has telephoned the fire’s location. The 
central office relays the information to all the other sta¬ 
tions in the city. 

An alarm of this type is called by the fire department a 
’’company still” and, with the exceptions noted, is handled 
like other still alarms. 

We are standing, let us say, before box No.427, The number, 
however, does not appear on the outside of the box, nor even 
on the inside after we have opened the outer door. Having 
opened the outer door of the box,we see a flat metal surface 
which has a slot in it. At the top of the slot a short brass 
handle sticks out and points toward us. The instructions on 
the flat surface tell us to ’’pull the handle down once and 
let go.” We follow instructions, and immediately a whirring 
sound comes from the inside of the box, 

A clock mechanism, driven by a spring, was wound by pulling 
down the little handle, and set a chain of gears in motion. 
The last gear wheel in the chain, instead of being of brass 
or steel like the other gears, is made of hard rubber—and 
some of its teeth are missing. In this particular box, No. 
427, on the circumference of the little wheel there are four 
teeth, and then one missing; two teeth, and another tooth 
missing; and finally, seven teeth, with more teeth missing 
between the last of the seven and the first four we counted. 


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That wheel, driven by the clockwork, revolves and its teeth 
operate a small telegraph key, sending to the central alarm 
office signals corresponding to the spacings of its teeth— 
that is, four dots and a pause, two dots and a pause, and 
seven dots and a longer pause before beginning all over 
again. A box may send such a signal as many as sixteen times 
with one pull of the signal handle or hook. 

No sooner had we pulled that hook than in the central alarm 
office an operator is standing at attention before telegraph 
sending keys. As the signal is received from our box, its 
number is transmitted throughout the city. No mistake about 
the number of the box which has been "pulled” is possible, 
for our signal has been received in the alarm office not 
only on a telegraphic sounder by also on a bell and on a 
device which has printed marks corresponding to the sound 
signals on a strip of paper tape. The alarm office operator 
sends the box signal twice on one transmitting key and then 
twice more on another similar key next to the first. 

On a broad shelf in the fire houses are two glass cases each 
containing several instruments. There are also push buttons 
and a telegraph sending key. This shelf with the instruments 
and buttons is known as the watch desk. One of these instru¬ 
ments is the "register." It looks and sounds something like 
a stock ticker. It stands off by itself on one side of the 
watch desk. As the box signals come in, a strip of tape on 
which are ink marks, indicating the number of the box, is 
fed from the register. This tape record is similar to that 
in the alarm office except that the tape in the alarm office 
was operated through the signal which came from the box, 
while the register tape in the fire station is marked through 
signals which have been retransmitted by the alarm office 
operator. 

The tape which is coming from the register and feeding over 
the edge of the desk into a waste basket, is marked by four 
dots, a space; two dots, a space; seven dots,a longer space. 
The register prints that set of markings four times, twice 
from the signals sent over the first alarm office key and 
twice from the second. The sets of signals have been sent 
over two different lines. As long as both lines are in work- 


( 14 ) 




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ing order—and they usually are-- each set of box signals 
will come in four times. If, however, as happens in rare 
cases, one of the lines is out of order at some particular 
fire house, the box signal will still come in twice on the 
line which is working and will be printed on' the register 
tape. 

The devices which feed the register tape and make the ink 
marks on it are operated by a clockwork mechanism which is 
wound every day. But it is the electric current of the sig¬ 
nal which trips the device,meanwhile tapping a bell in uni¬ 
son with the ink markings. 

The first two rounds of the box signal came in not only on 
the register but also on the telegraphic sounder in the other 
of the two glass cases on the watch desk. This second in¬ 
strument is called the "joker,” a term which has been the 
subject of much speculation on the part of persons in the 
fire department as well as of outsiders. 

Theories as to the origin of the name are numerous. Two of 
the more acceptable explanations of why the ”joker" was so 
named are: first, that several different sorts of signals 
are sent over the line, instead of only one, as is the case 
of the ordinary telegraphic sounder; second, that in the 
early days of the telegraphic fire alarm department messages 
were sent in a code which differed from ordinary Morse. 

Technical men may call the two lines over which box signals 
are sent the primary and secondary alarm lines. To Chicago 
firemen these two circuits have long been known as the 
"joker" line and the "alarm" line. The reason for these com- 
monly-used names is evident—the first two rounds of signals 
operate the "joker" as well as the register, while the last 
two rounds come in on the alarm register only. 

The last two rounds of box signals, that is, those sent over 
the alarm line, will also ring a big firehouse gong, unless 
someone holds down the appropriate push button on the watch 
desk. Bor most of the box alarms received at any one sta¬ 
tion, the man on watch does press the "hold down" button 
while the last two rounds of an alarm are coming in. Sine e 


( 15 ) 


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all box alarms go to all fire stations in the oity, each 
company responds to only a small proportion of the alarms 
received. 

When the alarm gong rings, the firemen take it for granted 
that the signal is for a fire in their district and rush to 
their places on the apparatus. To allow the alarm gong to 
ring for fires other than those requiring the services of 
the company or companies at a house would be confusing. 

Whether a company should respond to any particular box alarm 
is never a matter of doubt. At the watch desk of each com¬ 
pany is a wall chart which shows the numbers and locations 
of all boxes in the district covered by apparatus from that 
house on first box alarms. At the desk also is a map showing 
the territory in which the company responds to still alarms, 

When a box alarm comes in for a company, the man on v/atch 
lets the gong ring on the last tvm> rounds, the men rush to 
their places, and are on their v T ay with a speed that only a 
person who has seen the performance can appreciate. The same 
thing is happening in the quarters of each of the half dozen 
or more companies which are scheduled to answer alarms from 
that particular box. 

Meanwhile,men on watch in many other fire houses in the city 
have been looking up that same box number in their ”running 
card” files. The ’’running files” are file cards on which the 
various companies are listed, along with their assigned area 
of operations. By referring to them man on watch can deter¬ 
mine whether, in the event of a second alarm from that same 
box, their companies would move either to the fire or to an¬ 
other station vacated on the first alarm. 

After a second alarm every company in the city knows from 
its running-card file just w T here the box is located and is 
prepared to move if a succeeding alarm should make it neces¬ 
sary. With each additional alarm more companies move from 
their houses and the interest of the firemen who have not 
yet been called becomes more intense. 


( 16 ) 





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At the Central Alarm Office 


In the city hall alarm office, a second alarm starts activi¬ 
ties resembling those of a busy train dispatcher’s quarters. 

An operator throws a switch and an enormous wall map of the 
city gleams with several hundred lights. Each light repre¬ 
sents a fire station. The lights shine through frosted glass 
discs. A white disc with red numbers indicates an engine 
house. A red disc with white numbers marks the location of 
a hook and ladder company. If two companies have quarters 
in the same house,the lighted disc on the wall map shows the 
number of the engine company on the upper half and of the 
truck company on the lower half, 

Each light has its own button on a switchboard near the map. 
When a company leaves its quarters, an operator turns off 
the corresponding light, whether the company is answering an 
alarm or is on its way to take the place of a company which 
has gone to the fire. The absence of lights at the map loca¬ 
tions of companies which are at a fire or are moving shows 
clearly that the territories usually served by those compa¬ 
nies are temporarily without maximum fire protection.Shou 1 d 
a fire break out in a district from which the regular compa¬ 
ny has gone,the alarm office operator would summon the near¬ 
est available company. 

During the course of an extra-alarm fire, a wall-map light 
goes on occasionally in a part of the map which had a moment 
before been dark, shovang that a company’s quarters have 
again been occupied, wrhether by the regular company or by a 
substitute. Even during a large fire certain pieces of ap¬ 
paratus are not needed. In such cases the officer in com¬ 
mand sends the unneeded companies home and they inform the 
alarm office of their return by signalling 5-3-5 with the 
company’s code .signature. Likewise, when a company reaches 
a station to which it has been assigned temporarily,it gives 
the ’’return to quarters” signal, 3-3-5, with the signature 
of the company whose place is being taken and then the sig¬ 
nature of the occupying company. 


( 17 ) 












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The alarm office operator in charge during a large fire is a 
busy man. He must know what houses are temporarily vacant 
and what companies are available for service. He must see 
that officers at the fire are furnished with all the appara¬ 
tus and men that may be needed. In addition to all this, he 
must see that companies which are not on duty at a fire are 
relocated so as to furnish the greatest possible protection 
against fires in other parts of the city. 

We have, thus, followed the course of a box alarm from the 
time the signal hook was pulled to the time the apparatus 
started for the fire. Let us now see how a still alarm is 
handled. The procedures differ greatly. 

The still alarm, in practically all cases, comes into the 
central office by telephone. If the fire does not appear to 
be serious, the operator will send a direct call to the en¬ 
gine company nearest the fire. The engine is usually the 
only piece of apparatus sent to extinguish a small prairie 
fire or an automobile burning in the street. But, whenever 
the still alarm involves a fire in a building, a hook and 
ladder company also responds. 

The manner in which still alarms are sent to companies dif¬ 
fers slightly according to whether a company is located 
south or north of Pershing Road. 

South of Pershing Road,the operator signals a company on its 
particular ’’joker" line. The other four or five houses on 
the line also receive the telegraphic signal at the same 
time. Then over a telephone line.called today, as when tel¬ 
ephones were a novelty, the "talking" line—the alarm office 
tells the location and nature of the fire. At each of the 
other houses on that line the man on watch listened in on 
the directions and records on the company's slate or "board” 
the time of the alarm, the location of the fire,and the num¬ 
ber of the company to which the alarm was sent. 

The officer of the company called out has sent, by means of 
the telegraph key on the watch desk,the signal 5-5-5 follow¬ 
ed by the company’s number, thus telling the alarm office 
and the other stations on the line that his company was just 


( 18 ) 














leaving for the fire. The alarm office, in turn, sends the 
same message out over the "joker" lines of all the other 
companies in the city. 

The still alarm procedure we have described was used through¬ 
out Chicago up to a few years ago. However, in the district 
north of Pershing Road companies are now called out on still 
alarms by a somewhat different method. 

Each fire house in the north and central district is equip¬ 
ped with a loud speaker or amplifier, connected by direct 
telephone line with the central alarm office. Still alarms 
for a company come to it individually over the amplifier.The 
voice of the alarm office operator first calls the company 
by number,then gives the location of the fire and its nature. 
The announcement can be heard all over the main floor of the 
fire station. 

As the company is leaving the house,the officer in command 
strikes on his sending key the still alarm signal, 5-5-5 and 
his company signature. Then, over the "talking" line he re¬ 
peats the location of the fire for the information of the 
other companies on that same line. From this point on, the 
procedure is the same as that described for the south dis¬ 
trict. 

The work of the central alarm office,hovrever, is not finish¬ 
ed when it has sent to all the fire stations in the city no¬ 
tification that a particular company has left quarters in 
response to a still alarm. The danger may possibly prove to 
be greater than at first appeared. Accordingly, an alarm 
office operator has been looking up the number of the box 
nearest the fire. If another telephone call should come in, 
announcing that the flames were gaining headway, or if the 
officer of the comapny which responded to the alarm should 
call for additional apparatus, the office would send out a 
box alarm, whether or not the box had been "pulled." 

The companies scheduled to respond to an alarm from that 
particular box would then go directly to the fire, the exact 
location of which had been noted on the company "boards"when 
the first still alarm was sounded. Additional alarms from 


( 19 ) 



















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that same fire would be hanalea by regular box-alarm proce¬ 
dure . 

be have described two different methods of relaying still 
alarms to fire stations in two sections of the city,ana have 
thus far referred almost entirely to central alarm office 
operations as taxing place in the City Hall. There are ac¬ 
tually two alarm office districts. The purpose of the divi¬ 
sion is principally to avoid the running of lines too long 
to be operated economically. One district lies south of Per¬ 
shing Road, the other taxes in all of the city north of Per¬ 
shing Road. 

The Inglewood branch alarm office, at 6561 Wentworth Avenue, 
renders for the south territory" the services which the cen¬ 
tral alarm office performs for the rest of the city. Ail op¬ 
erations, however, ^re directed from trie central office and 
there run from this office about twice as many circuits as 
from the Englewood branch. The two offices are connected by 
direct lines, ana all alarms ana other signals sent to all 
the stations in either district are automatically repeated 
to all the other stations in the city. The two offices, for 
all practical purposes, operate as one. 

Some Technical Tidbits 


All the boxes in the city are not on one line. There are ap¬ 
proximately ninety separate lines, on each of which there 
are. on the average, thirty boxes connected In series. A 
series connection in electrical terms, may be compared to a 
chain—if one linx breaxs the chain is broxen. 

Through all of the boxes on a line a current flows constant¬ 
ly as long as the line is in order ana no box is sending a 
signal, bhen an alarm is being sent ihe current is inter¬ 
rupted at regular intervals «na the corresponding signals 
are received at the central office. 

To the uninformed person it might seam wasteful to xeep the 
box current flowing ail ihe time, but fctiore is a good reason 
for the practice. Alien a box is damaged or the circuit is 
broxen, the interruption becomes evident immediately- at the 

















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central alarm office and men are sent out to make the neces¬ 
sary repairs or adjustments. 

The amount of current required to give such protection is 
astonishingly small. Less current runs through each box line 
than is needed for one seven-watt night light. The box cur¬ 
rent uses only six watts. A watt is the product of the num¬ 
ber of volts times the number of amperes of an electrical 
current. Here are the figures. The box current has a 
strength of sixty milliamperes, that is, sixty one-thou¬ 
sandths of an ampere,and the line carries one-hundred volts. 
This small current is used, also, to send alarms from the 
central office to fire stations and to operate sounders, 
tape-marking devices, and big gongs. 

The small current causes these devices to operate—it does 
not work them directly. To accomplish this purpose there is 
used what is called an electrical relay. 

Relays are used extensively in telegraphic circuits of vari¬ 
ous kinds, such as, fire alarms, burglar alarms, and ordin¬ 
ary telegraphing. The relay is a means of using a compera- 
tively weak current to operate at a distance an electro-mag¬ 
net which opens or closes another circuit through which 
flows a current strong enough to do the necessary work. 

In the case of alarm circuits, for instance, the six-watt 
current from the alarm office closes the gong circuit at a 
fire house, just as if a switch were closed, and the bell is 
rung by a house current like that in your home—strong enough 
to operate even a washing machine motor. In like manner, 
registers and sounders are operated at fire stations by weak 
signals sent from the alarm office. 

The electro-magnet, through which the relay current does its 
work, differs greatly from the horse-shoe and bar magnets 
with which we have all played. Those are permanent magnets— 
the magnetism will last for years and years. An electro¬ 
magnet, on the other hand, is a temporary magnet. It works 
only when a current is flowing through the coil of the mag¬ 
net. 









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An electro-magnet consists, simply, of a piece of soft iron- 
around which copper wire is wound like thread on a spool.The 
strength of the electro-magnet depends on how many turns of 
wire there are around the iron core and how many amperes of 
current are made to flow through the wire. A comparatively 
weak electro-magnet may he used in a relay circuit to close 
the circuit through which a much stronger current flows. 
Other, more powerful electro-magnets operate the clapper of 
a hell, move the heavy bar of a telegraph receiver, actuate 
tape-marking devices, and perform the other duties necessary 
to the efficient operation of so extensive an alarm system 
as that which we have in Chicago. 


























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